U.S. patent number 7,001,559 [Application Number 10/006,384] was granted by the patent office on 2006-02-21 for production of pneumatic tires.
This patent grant is currently assigned to Bridgestone Corporation. Invention is credited to Hitoshi Nara, Akio Oobayashi, Haruo Toyoda.
United States Patent |
7,001,559 |
Oobayashi , et al. |
February 21, 2006 |
Production of pneumatic tires
Abstract
A method of highly efficiently producing pneumatic tires,
wherein both bead portions (B) of a green tire (G) are supported by
a pair of holders (24, 50) and opposite axial ends of a bladder
(25) are tightly attached to the holders (24, 50), respectively.
The holders (24, 50) are joined to each other and a fluid is
supplied into the bladder (25), to preliminarily inflate the
bladder (25) within the green tire (G). The green tire (G) is
transferred into a vulcanizer, together with the holders (24, 50)
and the preliminarily inflated bladder (25). A heat medium is
supplied into the bladder (25), to vulcanize the green tire (G) and
form a vulcanized tire (K). The preliminary inflation of the
bladder (25) at a location outside of the vulcanizer eliminates or
shortens the waiting time within the vulcanizer, thereby improving
the overall work efficiency and productivity at a tire factory.
Inventors: |
Oobayashi; Akio (Kodaira,
JP), Toyoda; Haruo (Kodaira, JP), Nara;
Hitoshi (Kodaira, JP) |
Assignee: |
Bridgestone Corporation (Tokyo,
JP)
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Family
ID: |
18845707 |
Appl.
No.: |
10/006,384 |
Filed: |
December 10, 2001 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20020079041 A1 |
Jun 27, 2002 |
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Foreign Application Priority Data
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Dec 12, 2000 [JP] |
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2000-376912 |
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Current U.S.
Class: |
264/237; 264/315;
264/326; 425/31; 425/33; 425/38; 425/58; 425/58.1 |
Current CPC
Class: |
B29D
30/0645 (20130101); B29D 30/0016 (20130101); B29D
30/0601 (20130101); B29D 30/0603 (20130101); B29D
30/0643 (20130101); B29D 2030/0647 (20130101); B29D
2030/0667 (20130101) |
Current International
Class: |
B29C
31/08 (20060101); B29C 35/04 (20060101) |
Field of
Search: |
;156/130.5,416
;264/326,237,DIG.65,315 ;425/38,40,48,50-58.1,DIG.39,31,33 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1-208-878 |
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Jan 1966 |
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DE |
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0-468-343 |
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Jan 1992 |
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EP |
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0-578-104 |
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Jan 1994 |
|
EP |
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0-578-106 |
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Jan 1994 |
|
EP |
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0-685-320 |
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Jun 1995 |
|
EP |
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1-090-729 |
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Apr 2001 |
|
EP |
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2-22016 |
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Jan 1990 |
|
JP |
|
Primary Examiner: Knable; Geoffrey L.
Attorney, Agent or Firm: Oliff & Berridge, PLC
Claims
What is claimed is:
1. A method for producing a pneumatic tire, comprising: supporting
both bead portions of a green tire by a pair of holders to which
opposite axial ends of a bladder are tightly attached separately
from a vulcanizer; joining the pair of holders to each other and
supplying a liquid into the bladder to preliminarily inflate the
bladder and green tire into a toroidal shape; transferring the
preliminarily inflated bladder and green tire into the vulcanizer,
together with the holders, after the preliminary inflation;
supplying a heat medium into the bladder after transfer to the
vulcanizer to thereby vulcanize the green tire and form a
vulcanized tire; transferring the vulcanized tire, together with
the holders and the bladder, from the vulcanizer to a post-cure
inflator; attaching the holders to a rotary shaft of the post-cure
inflator; rotating the rotary shaft of the post-cure inflator to
thereby cool the vulcanized tire; and accelerating cooling of the
vulcanized tire, by supplying a low-temperature liquid into the
bladder.
2. The method according to claim 1, wherein the liquid supplied
into the bladder for preliminary inflation is a high-temperature
liquid for preheating the bladder and green tire prior to transfer
into the vulcanizer.
3. An apparatus for producing a pneumatic tire, comprising: a
preprocessing machine comprised of (i) joining means for mutually
joining a pair of holders supporting both bead portions of a green
tire, respectively, and (ii) preliminary inflating means for
supplying a liquid into a bladder having opposite axial ends
tightly attached to the holders, respectively, to preliminarily
inflate the bladder and green tire into a toroidal shape; a
vulcanizer for supplying a heat medium into the bladder and green
tire, to thereby vulcanize the green tire and form a vulcanized
tire; a transfer device that transfers the preliminarily inflated
bladder and green tire, together with the holders, from the
preprocessing machine to the vulcanizer, and that transfers the
vulcanized tire, together with the holders and the bladder, from
the vulcanizer to a post-cure inflator; means for circulating
liquid through the bladder; and means for heating and/or cooling
the liquid as the liquid is circulated through the bladder.
4. The apparatus of claim 3, wherein the means for heating and/or
cooling the liquid is a heater.
5. The apparatus of claim 3, wherein the means for heating and/or
cooling the liquid is a heat exchanger.
6. An apparatus for producing a pneumatic tire, comprising: a
preprocessing machine comprised of (i) joining means for mutually
joining a pair of holders supporting both bead portions of a green
tire, respectively, and (ii) preliminary inflating means for
supplying a liquid into a bladder having opposite axial ends
tightly attached to the holders, respectively, to preliminarily
inflate the bladder and green tire into a toroidal shape; a
vulcanizer that supplies a heat medium into the bladder and green
tire, to thereby vulcanize the green tire and form a vulcanized
tire; a first transfer device that transfers the preliminarily
inflated bladder and green tire, together with the holders, from
the preprocessing machine to the vulcanizer; and that transfers the
vulcanized tire, together with the holders and the bladder, from
the vulcanizer to a post-cure inflator, and is usable to attach the
holders to a rotary shaft of the post-cure inflator; a rotator that
rotates the rotary shaft of the post-cure inflator to thereby cool
the vulcanized tire; a cooling acceleration system that accelerates
cooling of the vulcanized tire by supplying a low-temperature
liquid to the bladder; and a second transfer device that transfers
the cooled vulcanized tire, together with the holders and the
bladder, from the post-cure inflator to the preprocessing machine.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of, and an apparatus for
highly efficiently producing pneumatic tires.
2. Description of Related Art
As known in the art, in order to produce pneumatic tires, a green
tires with a substantially toroidal cross section is formed on a
building drum, and then transferred into a vulcanizing mold while
it is maintained open. The vulcanizing mold is then closed and a
heat medium at high temperature and high pressure is supplied into
a bladder of the vulcanizer, thereby inflating the bladder within
the green tire and vulcanizing the green tire in the mold to form a
product tire.
The above-mentioned conventional vulcanizing process suffers from a
problem that a substantial waiting time is required before
vulcanization of the green tire is actually started. It would be
highly desirable to eliminate or shorten the waiting time for the
vulcanizing process as far as possible, thereby improving the
overall work efficiency and productivity at a tire factory.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a
method and apparatus for producing a pneumatic tire, capable of
effectively eliminating or shortening the waiting time for the
vulcanizing process and improving the overall work efficiency and
productivity at a tire factory.
The inventors conducted thorough research and investigations
seeking for a solution of the above-mentioned problem, and arrive
at a unique concept of eliminating or shortening the waiting time
for the vulcanizing process by a preliminary inflation of the
bladder as an outside operation, i.e., at a location outside of the
vulcanizer and at a time point before the green tire is placed in
the vulcanizing mold.
According to one aspect of the present invention, there is provided
a method for producing a pneumatic tire, which comprises the steps
of: supporting both bead portions of a green tire by a pair of
holders to which opposite axial ends of a bladder are tightly
attached, respectively, joining holders to each other and supplying
a fluid into the bladder to preliminarily inflate the bladder
within the green tire, and transferring the green tire into a
vulcanizer, together with the holders and the preliminarily
inflated bladder, and then supplying a heat medium into the
bladder, to thereby vulcanize the green tire and form a vulcanized
tire.
According to another aspect of the present invention, there is
provided an apparatus for producing a pneumatic tire, which
comprises: a preprocessing machine comprised of (i) joining means
for mutually joining a pair of holders supporting both bead
portions of a green tire, respectively, and (ii) preliminary
inflating means for supplying a fluid into a bladder having
opposite axial ends tightly attached to the holders, respectively,
to thereby preliminarily inflate the bladder within the green tire;
a vulcanizer for supplying a heat medium into the bladder within
the green tire, to thereby vulcanize the green tire and form a
vulcanized tire; and transfer means for transferring the green tire
together with said holders and the preliminarily inflated bladder,
from the preprocessing machine to the vulcanizer.
With the method and apparatus according to the present invention,
the holders supporting both bead portions of a green tire,
respectively, are joined to each other by the joining means, and a
fluid is supplied into the bladder to thereby preliminarily inflate
the bladder within the green tire. Thereafter, the green tire,
together with the holders and the preliminarily inflated bladder,
is transferred from the preprocessing machine to the vulcanizer,
and a heat medium is supplied into the bladder, to thereby
vulcanize the green tire into a vulcanized tire.
In this way, at a location outside of the vulcanizer and at a time
point before the vulcanizing operation, the green tire is combined
with the holders and bladder, and the bladder is preliminarily
inflated by supplying the fluid into the bladder. The assembly
comprised of the green tire, holders and preliminarily inflated
bladder can be delivered into the vulcanizer as it is, thereby
allowing vulcanization of the green tire to be immediately started,
and improving the overall work efficiency and productivity at a
tire factory.
It is preferred that the fluid to be supplied for preliminarily
inflating the bladder is a fluid. In this instance, the holders,
the bladder and the green tire can be effectively heated in advance
of the vulcanizing operation, thereby allowing further shortening
of the waiting time for vulcanization.
Advantageously, the method according to the present invention
further comprises the steps of: transferring the vulcanized tire,
together with the holders and the bladder, from the vulcanizer to a
post-cure inflator, and attaching said holders to a rotary shaft of
said post-cure inflator; and rotating the rotary shaft of the
post-cure inflator to thereby cool the vulcanized tire. In this
instance, because it is unnecessary to discharge the heat medium
from the bladder after vulcanization, it is possible to further
improve the work efficiency. It is also unnecessary to separate the
vulcanized tire from the bladder before the post-curing and to
mount the vulcanized tire onto a rim of the post-cure inflator, and
it is thus possible to achieve substantial improvement in terms of
uniformity of product tires. Moreover, since the rim of the
post-cure inflator is substituted by the holders, it is possible to
achieve substantial simplification in terms of structure of the
post-cure inflator.
It is preferred that, upon post-curing of the vulcanized tire, a
low-temperature fluid is supplied into the bladder, to accelerate
cooling of the vulcanized tire. The vulcanized tire is thereby
rapidly cooled while avoiding a direct contact between the inner
surface of the vulcanized tire and the fluid.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be described in further detail
hereinafter, with reference to a preferred embodiment shown in the
accompanying drawings, wherein:
FIG. 1 is a schematic plan view showing one embodiment of the
apparatus for performing the method according to the present
invention;
FIG. 2 is a sectional view taken along the line II--II in FIG.
1;
FIG. 3 is a sectional view taken along the line III--III in FIG.
2;
FIG. 4 is a half sectional view of the vulcanizer; and
FIG. 5 is a sectional view taken along the line V--V in FIG. 1.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to FIGS. 1, 2 and 3, reference numeral 11 designates
an apparatus suitable for performing the method according to the
present invention, for highly efficiently producing pneumatic
tires, which may be for passenger cars, for example. The apparatus
11 includes a preprocessing machine 12 that extends in the
fore-and-aft direction. The preprocessing machine 12 has a
stationary frame 13 supporting two sets of horizontal conveyers 14,
15 that are vertically spaced from each other. The conveyers 14, 15
extend in the longitudinal direction of the frame 13 and are
operated in opposite directions.
The conveyer 14 on the upper side transfers a green tire G
forwardly, i.e., toward the downstream end 14a of the conveyer 14.
It is assumed that the green tire G has been formed by a building
machine (not shown) and is laid horizontally on the conveyer 14.
The conveyer 15 on the lower side, in turn, has an upstream end 15a
that extends beyond the downstream end 14a of the conveyer 14
substantially by a distance That corresponds to the diameter of the
green tire G, and transfers a vulcanized tire K to a next
processing station. It is also assumed that the vulcanized tire K
is laid horizontally on the conveyer 15.
As shown in FIG. 2, a vertical supporting stand 18 is arranged at a
processing station R opposite to the upstream end 15a of the
conveyer 15. The supporting stand 18 is provided therein with a
column-like center post 19 that is fixed to the frame 13. The
center post 19 is raised and lowered by a cylinder (not shown),
between a lower limit position where a flange 20 to be described
hereinafter is in abutment with an upper surface of the supporting
stand 18, and an upper limit position indicated by imaginary line
in FIG. 2.
The center post 19 has an upper end whose outer periphery is
provided with the aforementioned flange 20 having an annular shape.
Above the flange 20, the center post 19 is further provided with a
plurality of substantially triangular pawls 21 that are
circumferentially and equidistantly spaced from one another and
adapted to swing about the upper end of the center post 19 about
their horizontal axes, respectively. The pawls 21 project from the
outer peripheral surface of the center post 19 when they are swung
radially outwardly by associated springs (not shown). The pawls 21
are retracted to become flush with the outer peripheral surface of
the center post 19 when they are urged radially inwardly against
the springs, respectively.
Reference numeral 24 designates a substantially cylindrical lower
holder carried into and placed onto the supporting stand 18. The
lower holder 24 is mounted with an axial end (i.e., lower end) of a
bladder 25. The lower holder 24 has a supporting portion 24a just
under the lower end of the bladder 25, so as to support the lower
bead portion B of the green tire G. The supporting portion 24a has
an outer diameter larger than that of the lower holder 24 at a
mounting portion thereof for mounting the bladder 25. As shown in
FIG. 3, the upper end portion of the lower holder 24 is formed with
a plurality of protruding portions 24b protruding radially
inwardly. The protruding portions 24b are spaced circumferentially
and equidistantly from one another so as to exhibit arcuate shape,
respectively.
Reference numeral 27 designates an upper holder body having a
diameter smaller than the inner diameter of the bead portion B of
the green tire G, and this upper holder body 27 is arranged above
the lower holder 24 and mounted with the other axial end (i.e.,
upper end) of the bladder 25. The upper holder body 27 is formed,
on its center axis, with a through-hole 28 having the same diameter
as the center post 19 so that the upper end portion of the center
post 19 can be penetrated through the through-hole 28.
When the center post 19 is raised from the lower limit position,
the pawls 21 are pushed into the center post 19 by virtue of the
through-hole 28 such that the upper end portion of the center post
19 is projected upwardly from the upper surface of the upper holder
body 27. The pawls 21 are subsequently passed beyond the
through-hole 28 so that the pawls 21 are swung and projected from
the outer peripheral surface of the center post 19 by the urging
forces of the associated springs, respectively. By continuously
raising the center post 19 thereafter, the flange 20 is caused to
abut onto the lower surface of the upper holder body 27, so that
the upper holder body 27 is lifted up to a position indicated by
the imaginary line in FIG. 2 to thereby extend the bladder 25 into
a substantially cylindrical shape.
Reference numeral 31 designates a joint ring rotatably coupled to
the inner periphery of the upper holder body 27. The joint ring 31
has a lower end of a diameter slightly smaller than the inner
diameter of the protruding portion 24b. As shown in FIG. 3, the
joint ring 31 is formed, at the outer periphery of its lower end,
with radially outwardly protruded portions 31a of the same number
as the protruding portions 24b. The protruding portions 31a are
spaced circumferentially and equidistantly from one another so as
to exhibit arcuate shape, respectively.
Reference numerals 32 designate vertical rotary shafts that are
rotatably supported by the upper holder body 27 near the inner
periphery of the joint ring 31. Each rotary shaft 32 has an upper
end provided with a clutch piece 33 for preventing the rotary shaft
32 from falling from the upper holder body 27. Further, each rotary
shaft 32 has a lower end provided with a pinion 35 to be meshed
with internal teeth 34 formed at the inner periphery of the joint
ring 31. As a result, in a state where the protruding portions 31a
of the joint ring 31 are positioned between the protruding portions
24b of the lower holder 24, respectively, when the joint ring 31 is
rotated by the rotary shafts 32 such that the protruding portions
24b and protruding portions 31a are vertically overlapped with each
other, the lower holder 24 and upper holder body 27 are joined to
each other.
Reference numeral 38 designates a cylindrical elevating stand
supported, in a manner to be raised and lowered, by the fixing
frame 13 just above the supporting stand 18. The elevating stand 38
can be raised and lowered by a cylinder, not shown, toward and away
from the supporting stand 18. The elevating stand 38 has an outer
periphery of its lower end, coupled with a rotary ring 39 coaxial
with the elevating stand 38.
Reference numerals 40 designate motors fixed to the elevating stand
38. Each motor 40 has an output shaft 41 provided with a pinion 42
that is meshed with internal teeth 43 formed at the inner periphery
of the rotary ring 39. When the motors 40 operate to rotate the
pinions 42, respectively, the rotary ring 39 is rotated about a
vertical axis, while being supported by the elevating stand 38.
Reference numeral 45 designates an upper bead ring capable of
supporting the upper bead portion B. The upper bead ring 45 has an
upper surface formed with a plurality of joining holes 46 each
having an elliptical opening portion and a circular interior end.
Reference numerals 47 designate cylinders mounted at the lower
portion of the rotary ring 39. Each cylinder 47 includes a piston
rod 48 having a tip end fixed with a joining piece 49 having a
substantially same shape as the opening portion of each joining
hole 46. The upper bead ring 45 is joined to the rotary ring 39,
when piston rods 48 are protruded from the associated cylinders 47,
respectively, such that the joining pieces 49 are passed into the
bottoms of the joining holes 46 via opening portions of joining
holes 46, and then the cylinders 47 are rotated by angles of
90.degree. by a rotating mechanism, not shown.
The upper holder body 27 includes an upper end portion having an
outer periphery formed with a plurality of protruding portions 27a
similarly to the protruding portions 24b of the lower holder 24.
The upper bead ring 45 includes an upper portion having an inner
periphery formed with protruding portions 45a, similarly to the
protruding portions 31a of the joint ring 31 and at the same number
as that of protruding portions 27a. As a result, in a state where
the upper bead ring 45 is joined to the rotary ring 39 by the
cylinders 47 and joining pieces 49, when the elevating stand 38 is
lowered to the lower limit position so that the protruding portions
45a of the upper bead ring 45 have passed through between the
protruding portions 27a of the upper holder body 27. The rotary
ring 39 is then rotated by the motors 40 such that the protruding
portions 27a and protruding portions 45a are vertically overlapped,
when the upper bead ring 45 is integrally joined to the upper
holder body 27.
Thereafter, when the cylinders 47 are rotated so that the piston
rods 48 are retracted to thereby pull the joining pieces 49 out of
the joining holes 46, respectively, the joint between the upper
bead ring 45 and rotary ring 39 is released. In this way, when the
upper bead ring 45 is joined only to the upper holder body 27, the
upper holder body 27 and upper bead ring 45 cooperatively
constitute an upper holder 50 that is paired with the lower holder
24.
Reference numerals 53 designate motors fixed to the lower end of
the elevating stand 38. Each motor 53 includes an output shaft 54
having a tip end provided with a clutch piece 55 to be coupled to
the associated clutch piece 33 when the elevating stand 38 is
lowered to its lower limit position. When the clutch pieces 33, 55
are mutually coupled, the motors 53 are operated to rotate the
pinions 35 and thereby rotate the joint ring 31 while being
supported by the upper holder body 27.
The above-mentioned joint ring 31, rotary shafts 32, clutch pieces
33, pinions 35, motors 53 and clutch pieces 55 cooperatively
constitute joining means 56 for mutually joining the paired lower
and upper holders 24, 50 for supporting both bead portions B of the
green tire G, respectively.
Reference numeral 59 designates an elevating rod supported, in a
manner to be raised and lowered, by the elevating stand 38. The
elevating rod 59 is coaxial with the center post 19 and can be
raised and lowered by a cylinder, not shown. The elevating rod 59
has a lower end fixed with a push-in cap 60 formed with a recess
61, which is coaxial with, and of the same diameter as the
through-hole 28.
When the elevating rod 59 and push-in cap 60 are lowered and fitted
onto the center post 19 by the cylinder in a state where the
elevating stand 38 is at its lower limit position, the pawls 21 are
pushed radially inwards by the inner periphery of the recess 61.
When the center post 19 is lowered in this state, the center post
19 is allowed to pass through the through-hole 28 to thereby
downwardly escape therefrom, without being obstructed by the pawls
21.
Reference numerals 63 designate a pair of first fluid passages
formed within the lower holder 24. Each first fluid passage 63 has
one end opened at the outer periphery of the lower holder 24 so as
to communicate with a bladder space 64 confined by the lower holder
24, bladder 25 and upper holder 50. Meanwhile, the first fluid
passages 63 have the other ends opened at the lower surface of the
lower holder 24, such that these openings are communicated with a
pair of second fluid passages 65 formed within the supporting stand
18 when the lower and upper holders 24, 50 are supported on the
supporting stand 18.
Reference numeral 66 designates a circulation passage having both
ends connected to the respective ends of the second fluid passages
65. The circulation passage 66 is interposed therein with a heater
67 and a hydraulic pump 68. The circulation passage 66 is
communicated, via a switching valve 69, with a fluid source 70 for
supplying a fluid such as inert gas, steam or hot water heated to a
high temperature. As a result, when the switching valve 69 is
opened, the fluid from the fluid source 70 is supplied into the
bladder space 64 via circulation passage 66, to thereby inflate the
bladder 25 into a substantially toroidal shape within the green
tire G.
When the green tire G and bladder 25 have been inflated to the
predetermined toroidal shape, the switching valve 69 is switched to
its closed state. Thereafter, the hydraulic pump 68 is operated so
that the fluid within the bladder space 64 is brought to and heated
by the heater 67 via the first fluid passage 63 and second fluid
passage 65 and then returned to the bladder space 64 via the first
fluid passage 63 and second fluid passage 65, such that the fluid
is always kept at a predetermined and constant high
temperature.
The first fluid passages 63, second fluid passages 65, heater 67,
hydraulic pump 68 switching valve 69 and fluid source 70
cooperatively constitute inflating means 71 for supplying the fluid
heated to the higher temperature into the bladder 25 (i.e., bladder
space 64) having the opposite axial ends attached to the paired
lower and upper holders 24, 50 to thereby inflate the bladder 25
within the green tire G. Reference numerals 72, 73 designate
temperature sensor and pressure sensor for detecting the
temperature and pressure of the fluid within the bladder 25,
respectively.
Turning back to FIG. 1, reference numeral 75 designates transfer
means capable of moving in the fore-and-aft direction while being
guided by the frame 13 The transfer means 75 has a gripping
mechanism 76 capable of being raised and lowered and of gripping
the bead portions B of the tire from the radially inner side.
The transfer means 75 is capable of gripping, by the gripping
mechanism 76, the green tire G transferred to the downstream end of
the conveyer 14, i.e., up to a delivering station H, and then
transferring the green tire G onto the lower holder 24, when the
elevating stand 38 has been raised up to its upper limit position
and the upper holder 50 has been raised up to its upper limit
position indicated by the imaginary line in FIG. 2. The transfer
means 75 is also capable of gripping the vulcanized tire K on the
lower holder 24 by the gripping mechanism 76 and then transferring
the vulcanized tire K to the upstream end of the conveyer 15, i.e.,
up to a takeout station J.
The above-mentioned stationary frame 13, conveyers 14, 15,
supporting stand 18, elevating stand 38, rotary ring 39, motors 40,
cylinders 47, joining means 56, push-in cap 60, inflating means 71
and transferring means 75 cooperatively constitute the
preprocessing machine 12.
In FIGS. 1 and 4, reference numeral 80 designates a vulcanizer
installed in front of the preprocessing machine 12. The vulcanizer
80 has a lower base 81 provided thereon with a lower mold 82. The
lower mold 82 has its upper surface formed with a shaping surface
83 for shaping a sidewall portion S and the bead portion B of the
green tire G.
Reference numeral 84 designates an upper base installed in a manner
to be raised and lowered above the lower base 81. The upper base 84
can be brought away and toward the lower base 81 by raising and
lowering the upper base 84. Reference numeral 85 designates an
upper plate installed just under the upper base 84. The upper plate
85 is mounted to a lower end of a vertically extending piston rod
86 of a cylinder which, in turn, is mounted to the upper base
84.
As a result, the operation of the cylinder allows the upper plate
85 to be raised and lowered, independently of the upper base 84.
The upper plate 85 has a lower surface fixed with an upper mold 87.
The upper mold 87 has a lower surface formed with a shaping surface
88 for shaping the sidewall portion S and bead portion B of the
green tire G.
Reference numeral 90 designates an outer ring installed so as to
surround the upper plate 85 from the radially outer side thereof.
The outer ring 90 has an upper end fixed to the radially outer end
of the upper base 84. Also, the outer ring 90 has an inner
periphery formed with a surface 90a inclined upwardly and radially
inwardly.
Reference numerals 92 designate a plurality of, here nine pieces
of, sector segments arranged in a manner to be juxtaposed in the
circumferential direction. These sector segments 92 have upper ends
supported by the lower surface of the upper plate 85 at positions
radially outward of the upper mold 87, such that the sector
segments 92 are moveable in the radial direction. Further, the
sector segments 92 have their inner peripheries provided with
sector molds 93 having radially inner surfaces formed with shaping
surfaces 94 for primarily shaping a tread,portion D of the green
tire G, respectively.
The sector segments 92 have their outer peripheries formed with
inclined surfaces 92a having the same inclination as the inclined
surfaces 90a of the outer ring 90. The inclined surfaces 92a and
the inclined surface 90a are coupled to each other by dovetail
joints, so as to be slidably engaged with one another. As a result,
by raising and lowering the outer ring 90 relative to the upper
plate 85, the sector segments 92 are moved radially and
synchronously by the wedging effect of the inclined surfaces 90a,
92a, while allowing the sector segments 92 to be supported by the
upper plate 85.
When the upper base 84 is lowered to its lower limit position, all
of the sector molds 93 are urged by the outer ring 90 toward the
radially inner limit where the neighboring sector molds 93 are
closely contacted with one another to thereby exhibit a continuous
ring shape. At this time, when the lower and upper holders 24, 50
in a joined state for supporting the green tire G are placed on the
lower mold 82, the upper holder 50 is closely contacted with the
upper mold 87 at its lower limit position and the upper, lower and
sector molds 87, 82, 93 are closed to thereby internally define a
vulcanizing space of toroidal shape for housing the green tire G
therein.
Reference numerals 95 designate heat medium passages formed within
the lower mold 82. The heat medium passages 95 are communicated to
the first fluid passages 63 of the lower holder 24, when the lower
and upper holders 24, 50 in a joined state are placed on the lower
mold 82. When the heat medium at high temperature and high pressure
is supplied into the green tire G, specifically into the bladder
25, from a heat medium source, not shown, the green tire G is
vulcanized while being pressed onto the shaping surfaces 83, 88,
94.
The above-mentioned lower base 81, lower mold 82, upper base 84,
upper plate 85, upper mold 87, outer ring 90, sector segments 92
and sector molds 93 cooperatively constitute the vulcanizer 80 for
vulcanizing the green tire G into a vulcanized tire K by supplying
the heat medium into the bladder 25. Since such a vulcanizer 80
does not require conventional center post, upper and lower clamp
rings and bladder, the vulcanizer 80 itself has a simplified
structure and can be fabricated inexpensively.
Reference numeral 98 designates a first transfer machine installed
between the preprocessing machine 12 and vulcanizer 80. The first
transfer machine 98 includes an arm 100 which is adapted to be
swung and raised and lowered and which has a tip end provided with
a gripping mechanism 99 for gripping the upper holder 50. The first
transfer machine 98 grips, by its gripping mechanism 99, the lower
and upper holders 24, 50 supporting the green tire G at the
processing station R, and then raises the arm 100 and swings the
same toward the vulcanizer 80 so as to transfer the lower and upper
holders 24, 50 up to just above the lower mold 82.
Subsequently, the arm 100 is lowered to place the lower and upper
holders 24, 50 onto the lower mold 82, and the lower and upper
holders 24, 50 are then released from the grip by the gripping
mechanism 99. In this way, the green tire G is transferred together
with the lower and upper holders 24, 50, from the preprocessing
machine 12 to the vulcanizer 80.
In FIGS. 1 and 5, reference numeral 101 designates a post-cure
inflator installed on one side of the processing station R. The
post-cure inflator 101 has a disc-like horizontal turntable 102 to
be intermittently rotated about a vertical axis by a motor (not
shown).
Rotatably supported on the turntable 102 are a plurality of, here 4
pieces of, rotary shafts 103 circumferentially and equiangularly
spaced from one another. The rotary shafts 103 are rotated about
vertical axes at lower speeds by motors (not shown), respectively.
Further, that rotary shaft 103, which is positioned at a receiving
station U of the post-cure inflator 101, receives the vulcanized
tire K together with the lower and upper holders 24, 50 from the
vulcanizer 80 by means of the first transfer machine 98.
Each rotary shaft 103 includes an upper end portion having an outer
periphery formed with a plurality of circumferentially spaced ball
apertures 104. These ball apertures 104 house therein coupling
balls 105, respectively, in a manner to be radially moveable.
Reference numeral 106 designates a cylindrical-wall like slot
formed within the rotary shaft 103 coaxially with the rotary shaft
103. The slot 106 is inserted therein with a cylinder body 108
including its upper end having an outer periphery formed with an
inclined surface 107.
When the cylinder body 108 is raised to thereby protrude the parts
of coupling balls 105 from the outer periphery of the rotary shaft
103 in a state where the lower holder 24 is placed on the rotary
shaft 103, the protruded portions of the coupling balls 105 are
inserted into a circumference groove 109 formed at the inner
periphery of the lower holder 24 so that the lower and upper
holders 24, 50 are attached onto the rotary shaft 103. Contrary,
when the cylinder body 108 is lowered, the coupling balls 105 are
engaged with the inclined surface 107 and moved radially inwardly,
so that the entire coupling balls 105 are fully retracted from the
outer periphery of the rotary shaft 103 into the rotary shaft 103.
This allows the lower and upper holders 24, 50 to be detached from
the rotary shaft 103.
When the lower holder 24 is attached to the rotary shaft 103 in the
manner described above, the first fluid passages 63 are
communicated to fluid passages 110 formed in the rotary shaft 103.
Thereafter, there is supplied into the bladder 25 a low-temperature
fluid such as cool water or cool air from a fluid source 112 via
circulation passages 111 communicated to the fluid passages 110,
while rotating the shaft 103 at a lower speed, to thereby
accelerate cooling of the vulcanized tire K. Once the interior of
the bladder 25 has been filled with the cool fluid, a switching
valve 113 is closed and the fluid within the bladder 25 is then
circulated by a pump 115 while cooling the fluid by a heat
exchanger 114, so that the vulcanized tire K is continuously
quenched.
Reference numeral 118 designates a second transfer machine
installed between the preprocessing machine 12 and the post-cure
inflator 101. The second transfer machine 118 includes a gripping
mechanism 119 and an arm 120, similar to the gripping mechanism 99
and arm 100 of the first transfer machine 98. After the cooling of
the vulcanized tire K, the second transfer machine 118 grips the
vulcanized tire K together with the lower and upper holders 24, 50
positioned at an unloading station V, transfers them to the
processing station R, and places the lower holder 24 onto the
supporting stand 18.
In operation, it is assumed that the conveyer 14 is operated so
that a green tire G is carried into the delivering station H. At
this time, the elevating stand 38 is kept stand-by at its upper
limit position, and the center post 19 is raised to its upper limit
position at the processing station R so as to raise the upper
holder body 27 up to its upper limit position indicated by the
imaginary line in FIG. 2. Thus, the bladder 25 is upwardly inflated
into a cylindrical shape. Simultaneously, the vulcanizer 80 is
performing vulcanization of a green tire C, while at the post-cure
inflator 101 those rotary shafts 103 carrying vulcanized tires K
are slowly rotated to thereby cool the vulcanized tires K though
the rotation of the turntable 102 has been stopped.
The transferring means 75 is then operated so that the gripping
mechanism 76 grips and raises the green tire G at the delivering
station H, and transfers the green tire G up to the processing
station R, i.e., up to between the elevating stand 38 and
supporting stand 18. The gripping mechanism 76 is then lowered
together with the green tire G, so as to place the lower bead
portion B of the green tire G onto the supporting portion 24a of
the lower holder 24, thereby supporting the supporting portion 24a
from the lower side. At this time, since the bladder 25 is extended
upwardly to exhibit the cylindrical shape as described above, the
green tire G is transferred down to the lower holder 24 without
being obstructed by the bladder 25. The transferring means 75 is
then returned to its initial position, after released from the
grip.
The center post 19 is now to be lowered. At this time, the pawls 21
have been swung by the urging force of springs so as to protrude
from the outer peripheral surface of the center post 19 By this,
the pawls 21 are hooked onto the upper surface of the upper holder
body 27 such that the upper holder body 27 is lowered integrally
with the pawls 21. Simultaneously, the switching valve 69 is opened
and the fluid heated to high temperature is supplied from the fluid
source 70 into the bladder 25 to thereby gradually inflate the
bladder 25 within the green tire G. Simultaneously with the
lowering of the center post 19, the elevating stand 38 is also
lowered.
Once the lower surface of the upper holder body 27 has abutted onto
the upper surface of the lower holder 24, the lowering of the
center post 19 is to be stopped. At this time, the bladder 25 is
inflated within the green tire G so as to have a substantially
toroidal cross section. Thereafter, the elevating stand 38 is
lowered until the upper bead ring 45 abuts onto the upper holder
body 27, and this lowering is then stopped. At this time, the upper
bead ring 45 supports the upper bead portion B of the green tire G
from the above. Further, the protruding portions 45a of the upper
bead ring 45 pass between the protruding portions 27a of the upper
holder body 27, and the clutch pieces 55 are coupled to the clutch
pieces 33 so that the motors 53 are coupled to the pinions 35,
respectively.
The motors 40, 53 are now driven to thereby rotate the pinions 42,
35 engaged with the internal teeth 43, 34, respectively, so as to
rotate the rotary ring 39 and joint ring 31 supported by the
elevating stand 38 and upper holder body 27, respectively, about
vertical axes. Once the protruding portions 27a and protruding
portions 45a as well as the protruding portions 24b and protruding
portions 31a are mutually vertically overlapped, respectively, the
motors 40, 53 are stopped. This couples the upper bead ring 45 to
the upper holder body 27 to thereby establish the upper holder 50,
and also couples the lower holder 24 and upper holder 50 to each
other.
In the above, once the green tire G and bladder 25 are inflated
into the substantially toroidal shape, the switching valve 69 is
switched into the closed state. Thereafter, the hydraulic pump 68
is operated so that the fluid within the bladder space 64 is
conducted to the heater 67 and heated thereby, and then again
returned into the bladder space 64, so that the fluid is always
kept at a predetermined higher constant temperature. In this way,
the lower and upper holders 24, 50, bladder 25 and green tire G are
heated in advance of the actual vulcanizing operation and they are
kept stand-by in this state until starting the vulcanization. It is
thus possible to eliminate the waiting time for heating them from
ordinary temperatures up to the predetermined high temperature, and
to thereby shorten the vulcanization time for green tires G.
Next, the cylinder is operated to lower the elevating rod 59 and
push-in cap 60 until abutting onto the upper holder body 27, to
thereby fit the push-in cap 60 onto the upper end portion of the
center post 19. This pushes the pawls 21 radially inwardly by the
inner periphery of the recess 61. In this state, the center post 19
is lowered to its lowered-limit position. At this time, the pawls
21 have been retracted into the center post 19, so that the center
post 19 is allowed to pass through the through-hole 28 to thereby
downwardly escape therefrom, without being obstructed by the pawls
21.
The cylinders 47 are then rotated so that the piston rods 48 of
cylinders 47 are retracted to thereby pull the joining pieces 49
out of the joining holes 46, respectively. Thus, the joint between
the upper bead ring 45 and rotary ring 39 is released. Thereafter,
the elevating stand 38 is raised to its upper limit position.
In this way, the green tire G, lower and upper holders 24, 50 as
well as bladder 25 are combined with one another and the fluid is
supplied into the bladder 25 to thereby inflate it, at a location
outside of the vulcanizer 80, here at the processing station R,
before the vulcanizing operation. Thus, the combined components can
be delivered into the vulcanizer 80 as they are, making it possible
to immediately start the vulcanizing operation, and thereby improve
the overall work efficiency.
Once the green tire G has been vulcanized and formed into the
vulcanized tire K at the vulcanizer 80, the upper base 84 and outer
ring 90 are raised. However, the upper plate 85 is kept stationary
at this time, so that the sector segments 92 and sector molds 93
are synchronously moved and radially outwards by the wedging effect
of the inclined surfaces 90a, 92a, while allowing the sector
segments 92, hence the sector molds 93, to be supported by the
upper plate 85. Thereafter, the upper plate 85, upper mold 87,
sector segments 92 and sector molds 93 are raised at the same speed
as the upper base 84, to thereby open the vulcanizer 80.
Next, the lower and upper holders 24, 50 supporting the vulcanized
tire K are gripped by the gripping mechanism 99, and the arm 100 is
then raised. Thereafter, the arm 100 is swung toward the post-cure
inflator 101 so as to transfer the gripped components toward just
above an empty rotary shaft 103 at the receiving station U. The arm
100 is then lowered so as to place the lower and upper holders 24,
50 onto the rotary shaft 103, and releases the lower and upper
holders 24, 50 from the grip by the gripping mechanism 99. In this
way, the vulcanized tire K is transferred from the vulcanizer 80 to
the post-cure inflator 101 together with the lower and upper
holders 24, 50 by the first transfer machine 98.
At this time, the cylinder body 108 is raised so that the portions
of the coupling balls 105 are protruded from the outer periphery of
the rotary shaft 103 and inserted into the circumference groove
109. Thus, the lower and upper holders 24, 50 supporting the
vulcanized tire K are attached to the rotary shaft 103. Thereafter,
the low-temperature fluid is supplied into the bladder 25 while
rotating the rotary shaft 103 at a low speed, thereby cooling the
vulcanized tire K. Once the interior of the bladder 25 has been
filled with the low-temperature fluid, the switching valve 113 is
closed and the fluid within the bladder 25 is circulated by the
pump 115 while cooling the fluid by the heat exchanger 114, thereby
continuously cooling the vulcanized tire K.
In this way, the vulcanized tire K is transferred from the
vulcanizer 80 to the post-cure inflator 101 together with the lower
and upper holders 24, 50 as well as the bladder 25, and the
vulcanized tire K is cooled by rotating the rotary shaft 103 of the
post-cure inflator 101 after the lower and upper holders 24, 50
have been attached to the rotary shaft 103. This eliminates the
necessity of time for discharging the heat medium from the bladder
25 after vulcanization, to thereby improve the overall work
efficiency.
Further, it becomes also unnecessary to separate the vulcanized
tire K from the bladder 25, and to mount the vulcanized tire K onto
a rim of a post-cure inflator which has been conventionally
provided. This allows to improve the uniformity of product tires.
Further, the conventionally provided rim is substituted by the
lower and upper holders 24, 50, thereby allowing simplification in
terms of structure of the post-cure inflator 101.
Since the low-temperature fluid is supplied into the bladder 25
upon cooling the vulcanized tire K as described above, the
vulcanized tire K can be rapidly cooled while avoiding a direct
contact between the inner surface of the vulcanized tire K and the
fluid.
Meanwhile, when the gripping mechanism 99 has released the lower
and upper holders 24, 50 from the grip by this mechanism, the arm
100 is swung toward the vulcanizer 80. When the gripping mechanism
99 has reached just above the processing station R midway through
the swing, the swinging of the arm 100 is stopped temporarily.
Next, the arm 100 is lowered and then the gripping mechanism 99
grips the lower and upper holders 24, 50 supporting the green tire
G kept stand-by in a pre-heated manner at the processing station
R.
Next, the arm 100 is raised and then swung up toward the vulcanizer
80. Further, the arm 100 is lowered until the green tire G is
placed onto the lower mold 82, whereupon the gripping mechanism 99
releases the lower and upper holders 24, 50 from the grip by this
mechanism. Thereafter, the arm 100 is raised and swung up to a
stand-by position between the vulcanizer 80 and preprocessing
machine 12.
Subsequently, the upper base 84 and upper plate 85 are
synchronously lowered such that the lowering of the upper plate 85
is stopped when the sector segments 92 have abutted onto the upper
surface, and then only the upper base 84 and outer ring 90 are kept
lowered. As a result, the sector segments 92 and sector molds 93
are pushed by the outer ring 90 and thus moved radially inwards,
while being supported by the upper plate 85. Then, when the upper
base 84 has lowered down to its lower limit position, the
neighboring sector molds 93 are closely contacted with one another,
to thereby exhibit a continuous annular shape. At this time, the
upper and lower holders 50, 24 in the joined state are closely
contacted with the upper and lower molds 87, 82 and clamped from
the above and below so that the green tire G is housed within the
vulcanizing space.
The heat medium at high temperature and high pressure is then
supplied into the green tire G, specifically into the bladder 25,
from the heat medium source via medium passages 95 and first fluid
passages 63. Thus, the green tire G is vulcanized while being
pressed onto the shaping surfaces 83, 88, 94. At this time, the
lower and upper holders 24, 50 are joined to each other, so that
the fluid force of the heat medium acting onto the lower and upper
holders 24, 50 is born by the joint ring 31, thereby allowing to
reduce the tightening force by the vulcanizer 80 upon
vulcanization.
Meanwhile, when the first transfer machine 98 has started transfer
of the lower and upper holders 24, 50 as well as the green tire G
from the processing station R toward the vulcanizer 80, the arm 120
of the second transfer machine 118 is swung up to the unloading
station V and then lowered so that the gripping mechanism 119 grips
the lower and upper holders 24, 50 supporting the vulcanized tire K
which has been cooled. At this time, the cylinder body 108 of the
rotary shaft 103 positioned at the unloading station V is lowered,
so that the coupling balls 105 are withdrawn from the circumference
groove 109, to thereby release the coupling between the lower and
upper holders 24, 50, on one hand, and the rotary shaft 103, on the
other hand.
Subsequently, the arm 120 is raised while gripping the lower and
upper holders 24, 50 and vulcanized tire K, and then swung toward
the processing station R so as to transfer the gripped lower and
upper holders 24, 50 and vulcanized tire K toward the processing
station R. The arm 120 is then lowered until the lower and upper
holders 24, 50 are placed onto the supporting stand 18, whereupon
the gripping mechanism 119 releases the lower and upper holders 24,
50 from the grip thereof. The arm 120 is then raised and swung
toward the stand-by position between the preprocessing machine 12
and post-cure inflator 101.
When the lower and upper holders 24, 50 and vulcanized tire K are
detached from the rotary shaft 103 at the unloading station V in
the above manner, the turntable 102 of the post-cure inflator 101
is rotated by 90.degree., so that the emptied rotary shaft 103 is
moved up to the receiving station U.
At this time, the temperatures of the lower and upper holders 24,
50 on the supporting stand 18 have been lowered down to the
substantially ordinary temperatures. It is thus desirable to
previously heat the lower and upper holders 24, 50 such as by an
electromagnetic induction heater (not shown), in preparation for
the next vulcanization. Next, the elevating stand 38 is lowered
down to its lower limit position, so that the rotary ring 39 is
abutted onto the upper bead ring 45 and the clutch pieces 33, 55
are coupled to each other. The piston rods 48 of cylinders 47 are
then protruded such that the joining pieces 49 are inserted into
the bottoms of the joining holes 46, respectively, and the
cylinders 47 and joining pieces 49 are rotated such that the rotary
ring 39 and upper bead ring 45 are coupled to each other.
Next, the motors 40, 53 are operated to thereby rotate the rotary
ring 39 and joint ring 31 until the protruding portions 45a are
brought to be positioned between the protruding portions 27a and
the protruding portions 31a are brought to be positioned between
the protruding portions 24b, respectively, to thereby release the
coupling between the upper bead ring 45 and upper holder body 27,
and the coupling between the lower holder 24 and upper holder 50.
Thereafter, the elevating stand 38 is raised up to its raised-limit
position together with the upper bead ring 45.
The center post 19 is then raised so that the pawls 21 of the
center post 19 are pushed into the center post 19 by the
through-hole 28, to thereby allow the center post 19 to pass
through the through-hole 28 and to protrude beyond the upper holder
body 27. Thereafter, the pawls 21 are swung by the urging forces of
the associated springs, respectively, to thereby protrude from the
outer peripheral surface of the center post 19. By continuously
raising the center post 19, the flange 20 is caused to abut onto
the upper holder body 27, so that the upper holder body 27 is
lifted up to the position indicated by imaginary line in FIG. 2 to
thereby extend the bladder 25 into the substantially cylindrical
shape.
The transfer means 75 is operated such that the vulcanized tire K
at the processing station R is gripped by the gripping mechanism
76, and then raised and transferred up to just above the takeout
station J. At this time, the bladder 25 has been upwardly extended
to exhibit the cylindrical shape as described above, so that the
vulcanized tire K can be lifted without being obstructed by the
bladder 25.
Next, the gripping mechanism 76 is lowered together with the
vulcanized tire K, to thereby transfer the vulcanized tire K onto
the upstream end portion of the conveyer 15. The conveyer 15 is
then operated to transfer the vulcanized tire K to a next station.
The transfer means 75 is thereafter returned to its initial
position.
What has been described above corresponds to one cycle of operation
according to the present invention, and this cycle is repeated so
as to successively produce pneumatic tires, one after another.
In the above-mentioned embodiment, the fluid has been supplied into
the bladder 25 just before the lower and upper holders 24, 50 are
joined to each other. However, it is possible according to the
present invention to supply the fluid into the bladder 25 after the
lower and upper holders 24, 50 have been joined to each other.
According to the present invention as described above, it becomes
possible to inflate the bladder by an outside preparation, to
thereby improve the overall work efficiency and productivity at a
tire factory.
While the present invention has been described above with reference
to a preferred embodiment shown in the drawings, it is needless to
say that various changes and/or modifications may be made without
departing from the scope of the invention as defined by the
appended claims.
* * * * *